Process for making archetypes.



M. BARRIOELLI. PROCESS FOR MAKING ARGHETYPES.

APPLIOATION IILED JUNE 2, 1904.

909,980.. Patented Jan. 19, 1909.

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WITNassES \NVENTOR Improvement in Processes Archetypes; and {I '1 dohereby Maualzlo BARRICELLI, F ROME, ITALY.

rnocnss ron me ancnn'rms.

Specification of Letters Patent.

Patentedlan. 19, 1909.

' Application am June 2, 1904. Serial at. 210,769..

To all whom 'it may concern:

Be it known that I, NIAURIZIO Bnmuonnm, a subject of the King of Italy,residing at Rome, Italy, have invented a new and usefor Making sea rs.the following to' be a full, clear, and exact de scription of the same.

As is well known, photographic negatives have been used hitherto onlyfor the positive reproduction on sensitized paper, or for the productionof cliches or stereo-types or other similar preparations sensitive tolight.

The object of the present invention is to transform the negatives intoarchety es by which the positives can be printed w1th the same resultsas with collography the photographic negatives become stereotype plates,and can be substituted also for the ordinary photographic cliches.

The well known action which chrome salts exercise on gelatin isgenerally utilized in graphic arts, and specially in collotypy andphotoreliefs. It is further known that gelatins treated with a solutionof chrome salts and exposed afterwards to the action of light, losetheir solubility, extensibility, and permeability and become capable ofreceivmg printing ink.

By ex osmg a plate of gelatin or chromated a1 umen to the light afterplacing the same under a photographic negative, each part of the gelatinor albumen which receives the action of the light that passes throughthe corresponding parts of the negative, will require more or less theaforesaid properties according to the greater or less transparency ofthe superposed ne ative. By immersing afterwards the gelatin plate inwater, the gelatin will swell up more or less on the different partsaccording to the intensity of the action of the light on those parts ofthe gelatin. We thus obtain a positive picture in relief, which can beused for several photomechanical operations and for. impressions forprinting ink. This process requires naturally an auxiliary plate as thenegative serves only as a screen to determine the intensity of theaction of the light on each particular part of the plate and for thisreason the negative itself could not be subjected to the aforesaidtreatment. In the process of photo-archetypy as hereinafter described,chrome salts are used in order to produce the positive relief picture,direct onthe negative itself, avoiding thus all other secondaryoperations such as the reversing of the pic ture, reproduction of otherpositives and. the like. The great advantages which this new process ofphoto-archetypy presents over the ordmary process with .thechrome-gelatin are quite evident.

- Referring to the accompanying drawings Figure 1. is a cross-sectionalview, showing the sensitive layer between the glass plate and a metallicplate; Fig. II is a diagrammatic VIBW, showing the refraction of lightfrom a polished a diagrammatic view, showing the refraction of lightfrom a polished metallic plate; Fig. IV is a cross-sectional view,showing the application of the invention with a layer of two parts, oneof which is not acted upon by the light.

The method ofworkin this process is as follows; After having 0 tained abromid silver gelatin photographic negative and having developed it bypreference in a solution of amidol and sulfite of soda, (otherdevelopers not excluded), and havin fixed the same in a bath ofhyposulfite of soda, and then dried in a dark place, the dried negativeis then immersed in a solution of bichromate of potassium or bichromateof ammonium and alcohol in suitable proportions according to the natureof the negative. Afterwards the negative is again dried in a dark placeand is then placed on a specular surface such as a silvered plate, orother polished metal plate, or a layer of mercury, or any otherreflecting surface is then applied on the negative film. The nega tiveis placed on' the reflecting metallic surface in such a manner (see Fig.I) that the layer 4 of sensitive substance shall be comprised betweenthe polished reflectingmetallic surface 3 of a metallic plate 1 and thesurface 6 of the glass plate 5 to which the sensitive layer is adherent.The film placed on the reflecting surface is now exposed to the actionof actinic light with the side of the glass plate turned towards thenatural or artificial light for the necessary period which depends onthe intensity of the light,

The use of a metallic mirror, instead of a glass one, gives a betterutilization of the action of light, as will be easily understood.Referring to Figs. II and III, if we consider a thick glass plate, oneof the polished surfaces (for example, 10) is spread with a layer ofamalgam, silver. or any other glass plate, and Fig. III is- "in .III)onth'e met dfic' mirror 14.

substance,- we notethat. an incident ray 13 of t under two re'fractionsin passing m the air. to the glass and from the glass to the air, aftera 'on on 10, instead of. simple reflection (as shown h vi a Fig. IV;which re resents asection of a metallic p ate 16 wit the negativesupplied thereuntowiththiggoportions of the. not reserved, asfacilitates expfanations let it be assumed that .the layer, 17, ds to apart not acted upon by the light and that the of sensitive substancecopart 17 shown by hatched lines correspond to a part acted uyion'by the phe seen, the hash ayer ofvsensltme material applied to the negative filmwill be ren dared more or less insoluble, according to ht r or lessthe'rayglgf the '11 passing t oug t negative Towa ds the part H, wherethe darkened layer is =of-very great thickness 'a ray of 1 light, normalto vthe surface, 119, of the glass ate 18, will, while passing throughthe tieve 21 on r said plate lose a part of its intensity in reachingthe sur ace 20, and the degree of insolubility produced in the ireshsensitive layer be smallest; towards kythesray of light will .keepalmost the whole of its intensity and the h ghest degree-0f insolubilitywill be obtained.v In

any case, the -ra of light normal to the mirror will he .redected'in itsown direction, so :that the'fieldof light, whose action producesinsolubility, is not only increased but automatically regulated, Jfor.the action of each reflected ray is in inverse proportionto the 1oss ofluminousdntensitg, that is to say in proportion to the work it has toper-term.

olished' surface of .11-

even surface. 'T

enposure aforesaid the negative is thoroughl cleansed in fresh water andafter it has 11 complete] dried, is ready for thephoto-archetype;photo-archewhich can igpe-fimeaning thereby a stamp ecty be used for(printin and from which-pictures can be nary impression as from acliche)'may be used. for producing impressions, with printing ink onpaper, cloth. or any other also be detached from the g ass plate andapplfleil to af surfafe of celluloid 11- on :1 met' ateororina t a '011'This positive relief pici drez g dls d be used for the r roduct-ion ofprinting blocks for galvano-p astics or typographic cliches.

This new photo-archetypy mayalsobe' applied to the three colorphotography, by transforming the three monochromlc nega; tives in threephoto-archetypes by which the positive picture is to be impressed with-the three respective colored printing inks,

and without the aid of the usual nets.

I claim:

A procas' for producing a photographic n tlve .transformable .into' anarchetype suitable for use in printing, consisting in sensitlzmg andapplying a fixed and dried bromid silver gelatin photographic negaeo'sitive icture'mi ht P P g tained'by an ord1-

